It is becoming increasingly difficult to manufacture portable electronic devices including a battery and a display that are relatively compact, structurally robust, and take advantage of the largest available viewing area.
In portable electronic devices, displays are frequently laminated to transparent cover lenses to improve optical performance and create a mechanical bond between the two parts. Since this bond is present over the entire viewing area of the display, it provides enough mechanical retention to eliminate the need for retaining the sides of the display by any other mechanisms. Thus, on either side of the display, one simply needs to have a thin cosmetic housing to cover the side of the display. However, in attempting to use a minimally thin cosmetic housing to cover the edge of the display, one encounters the problem of finding an appropriate connection mechanism between this cosmetic housing and other housings in the portable device that would not itself increase the device's size.
Further complicating the search for a viable connection mechanism is the desire for reduced device thickness to improve user comfort when the device is in use or being transported.
With regard to methods of making a transparent lens and plastic housing for a device, traditionally, the process of insert molding includes placing a stiff metal insert into an injection molding tool and then molding plastic features around the metal part. When complete, the plastic should be well integrated in the original metal part. Recently, advancements have been made in mold quality permitting pieces of glass or different transparent material to be used as the “insert” such that complex three-dimensional plastic geometry may be integrated with a sheet of transparent material.
In a portable device, it is desirable for the transparent cover lens over the display to be integrated with overmolded plastic features, but this disadvantageously creates limitations as to the potential geometry for the glass or transparent insert. Over the viewing area of the display, one desires the transparent cover lens to be substantially thin and flat to result in an undistorted image and a small size for the finished device. Additionally, one desires that this cover lens also be as narrow and short as possible so that the resulting device is a minimal size. Conversely, the glass or transparent insert mold process prefers a large amount of material beyond the display to improve the bond between plastic and glass or different transparent material and ensure that the overmolded plastic does not detach from the transparent insert in the finished product.
With regard to supporting transparent, and particularly glass, elements in a display device, portable electronic devices are exposed to frequent mechanical shocks over their lifespan, which can lead to display failures. Such displays are often laminated to a thick transparent cover lens, but the displays themselves are typically constructed using multiple sheets of thin glass, leaving them susceptible to breakage—especially at the edges of the glass sheets. Additionally, these thin sheets of glass often do not have matching widths or lengths as compared to other elements or housings, which may create a “ledge” of unsupported glass. The unsupported thin glass ledge acts as a cantilever if the device experiences mechanical shock, and is a potential source of display failures.
Skilled artisans will appreciate that elements in the Figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the Figures may be exaggerated relative to other elements to help to improve understanding of various embodiments disclosed herein.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing the specific details that are pertinent to understanding the various embodiments and not obscuring the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.